Dayo , I think Richard Just's argument needs one more shade of subtlety. Conservatives do not generally say they are not anti-gay. They say some version of what Alabama Sen. Jeff Sessions, who has just replaced Pennsylvania Sen. Arlen Specter as the ranking Republican on the Judiciary Committee said: "I don't think a person who acknowledges that they have gay tendencies is disqualified per se for the job."
The key phrase of this quote is "gay tendencies." Conservatives, especially religious conservatives, are OK with someone who has "gay tendencies." They do however have a problem with someone who acts on those gay tendencies. This is the new "enlightened" conservative stance, because it acknowledges that people are born gay, but still preserves the belief that "homosexual acts" are a sin. The Catholic Church takes a similar line, and Andrew Sullivan has written often and passionately about what's wrong with it.
I too look forward to a debate over a gay nominee, but not necessarily an openly gay one. The most interesting debate will happen over one of these is she or isn't she candidates Dahlia and I have discussed. Then the right will be in a serious bind. Technically, such a person will be living by the conservative rules, feeling one way but failing to act on it. But conservatives will surely be uncomfortable with such a person. So they will have to contort themselves to find new creative euphemisms to express their discomfort.